1. Field of the Invention
The present invention is directed to a method for producing a fibrous web including textile length fibers wherein a thickener is used to disperse long synthetic fibers to produce a consistency in the range of 0.1 to 0.16 weight percent fibers thereby permitting the furnish to be supplied to a high speed papermaking machine for forming a fibrous web.
2. Description of Background Art
Hithertofore, a fibrous web containing textile length fibers has been formed by wet forming the web on an inclined wire papermaking machine. One method forms a uniform web from an unfoamed dispersion of staple length natural or synthetic fibers in water containing a small amount of polymeric surfactant, wherein some of the surfactant is known as associative thickeners. In this method, polymeric surfactant of the type known as associative thickener consisting essentially of an ethylene oxide based urethane block copolymer having alternating blocks of polyethylene glycol and polyurethane as dispersants is used in water as the carrier for natural and synthetic fibers. Other polymeric surfactants known as associative thickeners consisting essentially of hydroxyethylcellulose having a long aliphatic side chain as the dispersant and thickener for natural and synthetic cellulose fiber is used in a water carrier.
In addition, methods for forming a nonwoven fibrous web containing textile length fibers, for example, synthetic fibers having a length to diameter ratio in the range of from about 300 to 3,000, in a wet papermaking process are known in the art. Generally, a viscous aqueous carrier comprising a dispersant and thickener is required for good dispersion of long thin flexible synthetic fibers, for example, 1.5 denier by 3/4 inch (0.019 mm) fibers. The long thin synthetic fibers tend to tangle and form flocs or knits in the finished nonwoven fabric when formed from an aqueous dispersion suitable for wet laying papermaking fibers on a papermaking machine.
Methods of forming a fibrous web containing textile length fibers by utilizing a wetlaid process on a conventional papermaking machine are disclosed in U.S. Pat. Nos. 4,822,452 and 4,925,528 which are owned by the same Assignee as the present invention. U.S. Pat. Nos. 4,822,452 and 4,925,528 are hereby incorporated by reference.